From b1c16ac978fd40ae636e629bb69a652df7eebdc2 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Mon, 1 Apr 2019 11:29:57 +0300 Subject: [PATCH] btrfs: Use kvmalloc for allocating compressed path context Recent refactoring of cow_file_range_async means it's now possible to request a rather large physically contiguous memory via kmalloc. The size is dependent on the number of 512k chunks that the compressed range consists of. David reported multiple OOM messages on such large allocations. Fix it by switching to using kvmalloc. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/inode.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 05ff09e8a200..b6d549c993f6 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include "ctree.h" #include "disk-io.h" @@ -1172,7 +1173,7 @@ static noinline void async_cow_free(struct btrfs_work *work) * async_chunk's, freeing it ensures the whole array has been freed. */ if (atomic_dec_and_test(async_chunk->pending)) - kfree(async_chunk->pending); + kvfree(async_chunk->pending); } static int cow_file_range_async(struct inode *inode, struct page *locked_page, @@ -1188,6 +1189,7 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page, u64 num_chunks = DIV_ROUND_UP(end - start, SZ_512K); int i; bool should_compress; + unsigned nofs_flag; unlock_extent(&BTRFS_I(inode)->io_tree, start, end); @@ -1199,7 +1201,10 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page, should_compress = true; } - ctx = kmalloc(struct_size(ctx, chunks, num_chunks), GFP_NOFS); + nofs_flag = memalloc_nofs_save(); + ctx = kvmalloc(struct_size(ctx, chunks, num_chunks), GFP_KERNEL); + memalloc_nofs_restore(nofs_flag); + if (!ctx) { unsigned clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DELALLOC_NEW | EXTENT_DEFRAG | -- 2.20.1